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HL: Fachverband Halbleiterphysik
HL 37: Poster IV
HL 37.27: Poster
Mittwoch, 20. März 2024, 18:00–20:30, Poster F
Tailored sample designs for ultrafast electron diffraction at high repetition rates — •Leonardo C. da Camara Silva1,2, Till Domroese1,2, and Claus Ropers1,2 — 14th Physical Institute, University of Göttingen, Germany — 2Max Planck Institute for Multidiscipinary Sciences, Göttingen, Germany
Ultrafast electron diffraction (UED) is a powerful technique to resolve structural dynamics in strongly-correlated materials on ultrafast timescales [1]. For these experiments, the high-coherence electron source of the Göttingen Ultrafast Transmission Electron Microscope (UTEM) [2] enables the formation of particularly narrow but highly collimated femtosecond electron pulses. The nanometric beam diameters give access to nanoscale heterogeneity that often decisively influences the dynamics [3]. Highest spatiotemporal resolution, however, is only achieved for low bunch charges, mitigating Coulomb-induced pulse broadening, such that diffraction signal critically depends on the available duty cycle of the experiment. Here, we characterize different sample designs tailored to confine the laser excitation volume and to efficiently dissipate the thermal load. This allows us to drastically enhance the available repetition rates in our UED measurements, investigating structural phase transitions in the charge-density wave material 1T-TaTe2 at rates up to 2 MHz.
[1] D. Filippetto et al., Rev. Mod. Phys. 94, 045004 (2022)
[2] A. Feist et al., Ultramicroscopy 176, 63-73 (2017)
[3] T. Domröse et al., Nat. Mater. 22, 1345-1351 (2023)
Keywords: Sample Preparation; Ultrafast Transmission Electron Microscopy; Charge-Density Waves; Ultrafast Electron Diffraction; Phase Transitions